You can install a font style in several ways, It is a very simple process.
1.Double click on font style and install
You can donwload required font style and double click on downloaded file then click on install button.
After installed, it will be available for typing.
2. Copy all font style to fonts folder in control panel
You can copy & paste all downloaded font styles to control panel font folder.
You can paste all copied sinhala fonts to that folder.